knuclehead is incorrectly written, and should be written as "Knucklehead" being its meaning:
It is not a word in the Spanish language, but English and is poorly written, lacks a K. The correct way is Knucklehead, which means installed. It is a reference of the first motorcycle Harley Davidson with distribution OHV ( Over Head Valvles - 41 overhead valves. It was manufactured in 1932.
